HYPOTHESIS: The hepatotoxic effects of hyperthermia (41-43 degrees) are primarily the result of lipid peroxidation of cellular phospholipids. Moreover, a major source of oxygen radical is through the normal catalytic action of xanthine oxidase. Also, effects on the liver will vary with several factors: a) temperature and time at temperature, b) hepatic glutathione content and c) normal liver vs. liver with cancer. The following specific objectives are designed to test this hypothesis: 1. The perfused rat liver will be used to study the effects of hyperthermia, 41-43 degrees, on the efflux of glutathione disulfide (GSSG), malonaldehyde (MDA), hydroperoxide and lysomsomal enzymes from the normal liver and liver with cancer. 2. Study the effects of temperature 35-45 degrees on the invitro activity of the enzymes xanthine oxidase with respect to generation of superoxide, superoxide dismutase (SOD) and lgutathione peroxidase. 3. Use the perfused rat liver, normal and with cancer, to study whether the effects of heat on the liver observed in Aim 1 can be favorably changed by use of allopurinol, addition of palmitate or octanoate, or addition of N-acetylcysteine or methionine.